Generally, secondary batteries refer to chargeable-dischargeable batteries such as lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, and the like.
Recently, as secondary batteries are applied to devices requiring high output voltages and large charge capacities, such as electric vehicles or hybrid electric vehicles, stack-structured battery modules, in which unit battery cells having an output voltage ranging from about 2.5 V to about 4.2 V are connected in series or parallel and stacked, are widely being used. Thus, there is a trend of a rapid increase in interests and requests regarding techniques that allow efficient cooling of a battery module and simplification and size reduction of a structure of the battery module.
However, as disclosed in Korean Patent Publication No. 10-2013-0021794 and the like, according to existing techniques, since battery cells are cooled only by a cooling pin which is interposed between the stacked battery cells and contacts an outer body of a battery cell, that is, a pouch case of the battery cell, there is a problem in that an electrode lead portion of the battery cell, which emits a relatively large amount of heat, may not be efficiently cooled.
In addition, as disclosed in Korean Patent No. 10-1415050 and the like, according to existing techniques, since a large number of cooling pins having a complicated structure are used to improve the cooling capability of a battery module, there are problems in that simplification or size reduction of a structure of the battery module is difficult, and that manufacturing costs of the battery module are increased.